The present invention relates to a guard ring used during coupling of a tool holder to a power drawbar of a machine tool spindle that shields the facing surfaces of a tool flange and spindle face that move together as the tool holder is tightened in place.
Presently machine tools using a standard taper drive tool system with a power drawbar to pull the tool holder and tool into the tapered socket on the spindle. The tool holder has a flange that surrounds the tapered shank of the tool holder which moves close to contact with the spindle face. The space between the flange and surface is close enough to pinch a careless finger.
Another problem with a standard tool system is that the power drawbar can rotate the tool holder when the threads of the drawbar and tool holder engage, which in the standard system, is before the tool holder is drivably engaged with the spindle. Particularly if the threads bind, the torque on the tool holder can cause it to spin and release from hand holding force.
Thus a guard for that not only covers the gap under the spindle face but also provides driving engagement between the spindle and tool before the drawbar and tool holder threads engage eliminates those problems.